The broadband wireless access standard IEEE 802.16 mainly includes two versions, i.e., a fixed broadband wireless access standard IEEE 802.16-2004 and a mobile broadband wireless access standard IEEE 802.16e. 802.16-2004 defines two types of network elements, i.e. Base station (BS) and Subscriber station (SS). Similarly, 802.16e also defines two types of network elements, i.e. Base station (BS) and Mobile Subscriber station (MSS, or Mobile Station, MS).
Currently, a BS communicates with a subscriber terminal (e.g. an SS or MSS) directly to exchange information with the subscriber terminal. The entire coverage of a network is limited because of the limited coverage of base stations (BSs). Furthermore, one BS is required to process information from a large number of subscribers simultaneously because each subscriber terminal communicates with the BS directly. This may bring adverse affect on the information processing performance for the subscriber stations, thereby resulting in a decrease in the throughput of the subscriber stations, and an adverse affect on the communication performance of the entire network.